I chose 1/8" which will require you to lower the bed pretty much as far as it goes but you can chose a thinner piece.

Next cut it into a 8x8 square. I used a Stanley razor cutter and just scored the front and back a few times, then snapped the excess pieces off.
I also cut the corners to prevent the sheet from touching any of the screws. For that I just used some snips. You can use a saw, dremel, or whatever you desire for these cutting steps.

Next I used an orbital sander with 120 grit paper to create a matte finish on one side. I slightly sanded the cut edges to make them smooth, both with the sander and by hand. On the other side I used 1000 grit paper to remove any unwanted scratches on the bottom. (This isn't a necessity)

Finally, I gave it a quick rinse of water and dried it. Placed it on the bed over the stock tak-like material and used two small binder clips to secure it on the bed. If binder clips bother you, take out your caliper for measurements and print yourself some lower profile bed clips.

When you re-level the bed, you may need to increase the space between the nozzle and bed just slightly. I used a business card and made it so the nozzle was slightly "grabby" towards the paper. Anything tighter and you might risk melting/fusing with the plate. If that happens just re-sand and repeat.

That's it! Works extremely well and is by far my favorite build plate material atm.